Endoscopic snare net

ABSTRACT

An endoscopic snare net comprises a net engaging a loop, such as by weaving the loop through a mesh of the net, and a tube having a lumen through which the net and loop may be extended and withdrawn by a control wire. The loop has one or more corners or a collared, free-floating slip tether or both thereof, which prevent the net from sliding free of the loop as the loop is retracted into the lumen of the tube, even if the loop is over-extended beyond the end of the tube.

CROSS RELATED APPLICATIONS

This application is a 371 U.S. national phase application which claimspriority to PCT/US2018/041872 filed Jul. 12, 2018 which claims priorityto U.S. provisional 62/531,470, which was filed Jul. 12, 2017, which isincorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The field relates to endoscopic devices, especially endoscopic snarenets.

BACKGROUND

Snare nets are known that tie a portion of the net to a cold loop orloops. Examples of known snare nets are found in U.S. Pat. Nos.8,016,838; 7,618,437; 6,814,739; 5,906,621; 5,759,187; 5,486,182;5,336,277; 5,201,740; and 5,190.542. However, all of these known snarenets have a difficult time forming a pocket for capturing a polyp orforeign object or have complex mechanisms or have excessive nettingmaterial that may snag or require a larger diameter lumen to passthrough. While some of complex systems solve one or more of theproblems, added complexity makes them potentially prone to failure andmay add substantial cost to a medical procedure.

SUMMARY

An endoscopic snare net device comprises a shaped loop, a net and a tubehaving a lumen configured and arranged to accept the introduction of theloop and snare net through the lumen of the tube. The lumen is definedby a wall of a tube, such as a polymer tube. Herein, “lumen” means theopen volume within a tube and is not limited to a biological lumen. Thetube wall may have a collar disposed within the lumen, which may befixed to the wall of a tube in a position at a distance from an end ofthe tube or may be free floating withing the tube around the controlwire. The shaped loop may be made of a resilient, flexible material,such as metal. For example, the metal may be a steel, nitinol, titaniumor alloys thereof. A distal end of the loop may be crimped and shaped toexpand as the distal end exits the lumen first. One or more crimpedcorners may be disposed adjacent to the distal end of the loop.

In one example, the loop has one or more resilient bends in the proximalend of the loop that cause the loop to open and remain open, when theloop is extended fully from the tube. For example, a crimped corner isprovided in addition to the one or more resilient bends that bias theloop to open when extended from the tube. In one example, the crimpedcorner is provided by bends in the loop, itself; however, the crimpedcorner serves a different purpose than the one or more resilient bendsthat bias the loop open. Instead of biasing the loop open, when the loopis extended from the tube, the crimped corner serves to secure a snarenet during closing, which may be attached to the loop only by a singleknot at the distal end of the loop, by weaving the loop through theopenings in the net and/or by a tether looped through the net at aproximal end of the loop. In one example, a loop without at least onecrimped corner results in the net riding forward on the loop as the loopis withdrawn into the tube. In contrast, a loop with at least onecrimped corner pulls the net into the tube with the loop. In addition, apair of crimped corners on opposite sides of the loop helped to form adistinct pocket within the net as the loop and net are pulled into thetube, as the loop closes. Even though the net is flat when the loop isfully deployed, as the loop is withdrawn, a pocket forms in the net thatmay be used to capture a foreign object while the loop closes around theforeign object.

In one example, the bends of the crimped corner do not form a loop (i.e.the crimped corner is open and does not loop around and cross overitself). Instead, in this example, the bends that form a crimped cornercomprise a first bend in a first direction, a second bend in a seconddirection, and a third bend in a third direction. The first bend isnearer to the proximal end of the loop than the other bends. A bend inthe loop creates an angle between the portion of the loop proceeding thebend and the portion of the loop after the bend. The first bend may bendthe loop such that the first portion of the crimped corner is directedmore inwardly, in a direction more toward an imaginary line extendingfrom a central longitudinal axis of the tube, for example, when the loopis extended from the tube.

For example, a portion of the loop disposed before a first bend (i.e.closer to the proximal end of the snare loop), may be divergingoutwardly from the imaginary line, when the loop is extended from thetube, and the first portion of the crimped corner after the first bendmay extend less outwardly divergent, substantially parallel or inwardlydivergent. Herein, “more outwardly divergent” means a greater angle,more away from the direction of the imaginary line extending from thecentral longitudinal axis of the tube. “more inwardly divergent” means alesser angle, more toward the direction of the imaginary line extendingfrom the same axis. In one example, the first bend changes the directionof the loop more inwardly divergent, the second bend changes thedirection of the loop more outwardly divergent and the third bendchanges the direction of the loop more inwardly divergent.

In one example, a more inwardly divergent first portion of the crimpedcorner is substantially parallel to the imaginary line, when the loop isextended from the tube. The term “substantially parallel” does not meanprecisely parallel. Instead, the term “substantially parallel” means nogreater than five degrees divergence, plus or minus, from parallel to animaginary line extending from the central longitudinal axis of the tube.In an alternative example, the first portion is inwardly convergent(i.e. an imaginary line extending from the first portion eventuallyconverges with the imaginary line extending from the centrallongitudinal axis of the tube, as both extend toward the distal end ofthe loop. In yet another example, the first portion of the crimpedcorner is outwardly divergent, but less so than the portion of the loopimmediately preceding the first bend of the crimped corner.

In one example, a floating tether anchor is sized with an inner diameterthat is greater than the outer diameter of a control wire passingthrough the inner diameter of the floating anchor, such that thefloating anchor is not secured to the control wire and readily slideslong the control wire within the tube. In one example, the outerdiameter of a tether anchor is greater than the inner diameter of thetube surrounding the tether anchor, such that the tether anchor issecured in a fixed position relative to the tube. In an alternativeexample, a floating tether anchor has an outer diameter that is lessthan the inner diameter of the tube surrounding the tether anchor, suchthat the floating tether anchor freely slides or “floats” within thetube.

A method of using a snare net comprises extending a net engaged on snareloop from a lumen such that the loop opens; positioning the net and loopendoscopically to retrieve an object, such as a foreign object or polyp;withdrawing the net and loop at least partially back into the lumen,causing the loop to at least partially close and creating a pocket inthe net, a crimped corner portion engaging a portion of the net near theproximal end of the loop, such that the net is pulled into the lumen bythe crimped corner, when the loop is withdrawn into the lumen.

In one example, an endoscopic snare net device comprises a shaped loophaving a distal end of the loop and a proximal end of the loop, thedistal end of the loop being shaped to expand as the distal end of theloop exits the lumen first, and the proximal end of the loop having oneor more corners existing the lumen after the distal end of the loop; anet; and a tube having a lumen configured and arranged to accept theintroduction of the loop and snare net through the lumen of the tube,

wherein the lumen is defined by a wall of the tube, and the net isengaged on the shaped loop such that the engaged loop is woven throughholes in the net such that the net is retained on the shaped loop, thenet being secured at the distal end of the shaped loop and, and the netengaging the one or more corners of the shaped loop at the proximal endof the shaped loop, the one or more corners being shaped such that theone or more corners retain the net from sliding forward on the shapedloop during extension of the shaped loop and net from the lumen andretraction of the shaped loop and net into the lumen.

For example, a shaped loop may be made of a resilient, flexiblematerial, such as a metal, for example, a metal selected of a steel,nitinol, titanium or alloys thereof. In one example, a steel loop isused. The tube may have a collar disposed within the lumen, and thecollar may fixed to the wall of the tube in a position at a distancefrom an end of the tube or may be free floating. Optionally, a tethermay be coupled to the collar at a first end of the tether and to the netat a second end of the tether, opposite of the first end. The tube mayhave a free floating collar within the tube and disposed around acontrol wire coupled to the shaped loop. The tether may be coupled tothe collar at a first end of the tether and to the net at a second endof the tether, opposite of the first end.

In one example, a length of the tether is selected such that the tetherengages the net withdrawing the net into the tube, when proximal end ofthe shaped loop enters the tube during retraction of the shaped loop andnet.

For example, one or more corners may be crimped and provide one or moreresilient bends that bias the loop to open when extended from the lumenin addition to any bends that bias the loop open. The one or morecorners secure a snare net on the loop during closing, and the net issecured to the distal end of the loop only by a single point ofattachment at the distal end of the loop, for example. The one or morecorners may comprise at least a first corner on a first side of theproximal end of the loop and a second corner on a second side of theproximal end of the loop, opposite of the first side such that adistinct pocket is formed within the net as the proximal end of the loopand the net are pulled into the tube, as the loop closes. The one ormore corners may be open such that the loop does not extend over anyother portion of the loop, i.e. the loop does not form a smaller loop bylooping over itself.

Each of the one or more corners may comprise a first bend in a firstbend angular direction, a second bend in a second bend angulardirection, opposite of the first bend angular direction, and a thirdbend in a third bend angular direction opposite of the second bendangular direction, arranged such that each of the one or more cornersextends outwardly from an imaginary line extending from a centrallongitudinal axis of the tube, when the loop is extended from the tube,for example. The first bend angular direction may be more inwardlydivergent than the angular direction of an adjacent portion of the loopcloser to the proximal end of the loop, the second bend angulardirection may be more outwardly divergent than the first bend angulardirection, and the third bend angular direction may be more inwardlydivergent than the second bend angular direction, whereby an outwardlyextending corner is formed at a outward vertex where the loop extendingalong the second bend angular direction diverges toward the third bendangular direction and an inwardly extending bend is formed at an inwardvertex where the loop extending from the first bend angular directiondiverges toward the second bend angular direction, for example. In oneexample, the one or more corners form at least one zig zag in a portionof the loop.

In one example, a loop anchor couples the loop to the control wire,wherein the collar is sized with an inner collar diameter that isgreater than an outer wire diameter of the control wire, and the loopanchor has a loop anchor outer diameter greater than the inner collardiameter of the collar, such that the collar cannot slide past the loopanchor outer diameter.

In one example, a method of using the endoscopic snare net comprisesextending the net and the loop from the lumen such that the loop opens;positioning the net and loop endoscopically to retrieve an object;withdrawing the net and loop at least partially back into the lumen,causing the loop to at least partially close and creating a pocket inthe net, one or more of the corners engaging a portion of the net nearthe proximal end of the loop, such that the portion of the net is pulledinto the lumen by the one or more corners, when the loop is withdrawninto the lumen.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings are illustrative examples and do not furtherlimit any claims that may eventually issue.

FIG. 1 illustrates an example of an endoscopic snare net.

FIG. 2 illustrates a detail view (A) of the example of FIG. 1.

FIG. 3 illustrates another example of an endoscopic snare net.

FIG. 4 illustrates a detail view of a tether as used with any of theprevious examples.

When the same reference characters are used, these labels refer tosimilar parts in the examples illustrated in the drawings.

DETAILED DESCRIPTION

FIG. 1 shows an example of an endoscopic snare net 10 comprises a net11, a loop 12 and a tube 13. The tube 13 may comprise a lumen throughwhich a cable 25 passes that may be used to extend and withdraw the net11 and loop 12. The loop 12 may be a wire, which may be flat or round incross section. The wire of the loop may pass through the net above andbelow the plane of the net weaving through the openings in the net. Thenet 11 is retained on the loop 12. A knot 23 may attach the net 11 to adistal end of the loop 22. For example, the distal end of the loop 22may be crimped to provide a bias force that opens the loop 22 when thedistal end 22 of the loop 22 is extended from the tube 13.

The cable 25 may be coupled to the loop 12 by a connector 21, such ascrimped connector, such that moving the cable forward deploys the loopand net and withdrawing the cable 25 closes and retrieves the loop andnet into the lumen of the tube 13. The cable and tube may be made anylength L.

For example, a tether 16 may be coupled to a coupling 24 provided withinthe lumen of the tube 13 on one end of the tether 16, and the other endof the tether 16 may loop around a portion of the net 11 and/or the loop12. In one example, the length of the tether is about the same as thedistance from the distal tip of the loop to the proximal end of the loopextending out of the lumen when the loop is fully extended. The tethermay loop around the net and the loop, preventing both from extended outof the lumen, completely, for example, as shown in more detail in theexample of FIG. 2.

The example of FIG. 1 shows a plurality of crimped corners 30, 40.Additional crimped corners may be added. Alternatively, only a singlecrimped corner may be provided, for example. In testing, a pair ofcrimped corners 30, 40 created a pocket in the snare net 11 as the loop12 is withdrawn into the lumen. The detail A in FIG. 1 is shown in moredetail in the example of FIG. 2. A first divergent portion of the loop37 extends from the lumen in this example, and a second divergentportion 36, after a bend in the loop 12, is more outwardly divergentthan the first portion of the loop. A first crimped corner bend 35causes a first portion 34 of the crimped corner to be directed lessoutwardly divergent. A second crimped corner bend 32 causes a secondportion 33 of the crimped corner to be directed more outwardly divergentthan any of the other portions. A third bend 31 causes a subsequentportion of the loop to be directed less outwardly divergent than thesecond portion 33 of the crimped corner 30, which continues in anarcuate oval shape until it nears the distal end 22 and knot 23.

Although not particular clear in the drawing, the location and angle ofthe portions of the crimped corners 30, 40 are not the same. In thecrimped corner 30 the first corner portion 34 is substantially parallel;however, in the crimped corner 40 the first corner portion is moreoutwardly divergent and closer to the lumen opening of the tube 13. Forexample, the angle α between the first portion of the crimped corner 34and the second portion of the crimped corner 33 may be greater than 90degrees (or an obtuse angle), less than 90 degrees (or an acute angle)or substantially 90 degrees, where “substantially 90 degrees” means 90degrees plus or minus 5 degrees, when the loop is fully extended fromthe lumen. In one example, an angle α is selected such that the angleprevents the net from sliding past the crimped corner 40, for example.

In another example, a tether 115 may be coupled with the snare net 11.For example, FIG. 3 shows an example of a loop 112 that does not havecrimped corners, and FIG. 4 illustrates a detailed view of a tether asused on any of the previous examples. A tether 115 may be coupled with anet 11 by looping the tether through the net at a distal end 118 of thetether 115, and coupling the proximal end 119 of the tether 115 to afloating tether anchor 117 by looping the tether 115 through the anchor117. The anchor 117 is referred to as a floating tether anchor, becausethe anchor 117 is not fixed to any other structure. The anchor isattached to neither the tube nor the wire 122. Instead, it slides or“floats” freely along the wire 122. One of the benefits of this floatinganchor is that the tether 115 need not pull on the net 11 when the netis deployed, even if the net is over-deployed. This may prevent the netfrom being torn or unraveled by the tether. Instead, the tether floatson the wire 122 until the user withdraws the net and loop back into thetube. Then, the anchor 117 may be snagged by an obstacle, such as theend of the connecting cannula 120 or the like. Alternatively, a separatecrimped cannula 121 may be crimped onto the control wire 122 and may actas the obstacle that engages the floating tether anchor 117. A space maybe provided between the anchor 117 and any such obstacle to preventsnagging prior to withdrawal of the loop and net back into the lumen ofa tube. In one example, a connecting cannula 120 may extend beyond theends of the snare loop. As shown in FIG. 4, a connecting cannula 120 maybe a crimped portion of a metal tube, which may be of the same materialused in hypodermic needles or the like, for example.

This detailed description provides examples including features andelements of the claims for the purpose of enabling a person havingordinary skill in the art to make and use the inventions recited in theclaims. However, these examples are not intended to limit the scope ofthe claims, directly. Instead, the examples provide features andelements of the claims that, having been disclosed in thesedescriptions, claims and drawings, may be altered and combined in waysthat are known in the art.

1. An endoscopic snare net device comprises: a shaped loop having adistal end of the loop and a proximal end of the loop, the distal end ofthe loop being shaped to expand as the distal end of the loop exits thelumen first, and the proximal end of the loop having one or more cornersexisting the lumen after the distal end of the loop; a net; and a tubehaving a lumen configured and arranged to accept the introduction of theloop and snare net through the lumen of the tube, wherein the lumen isdefined by a wall of the tube, and the net is engaged on the shaped loopsuch that the engaged loop is woven through holes in the net such thatthe net is retained on the shaped loop, the net being secured at thedistal end of the shaped loop and, and the net engaging the one or morecorners of the shaped loop at the proximal end of the shaped loop, theone or more corners being shaped such that the one or more cornersretain the net from sliding forward on the shaped loop during extensionof the shaped loop and net from the lumen and retraction of the shapedloop and net into the lumen.
 2. The endoscopic snare net of claim 1,wherein the shaped loop may be made of a resilient, flexible material.3. The endoscopic snare net of claim 2, wherein the resilient, flexiblematerial is made of a metal.
 4. The endoscopic snare net of claim 3,wherein the metal is of a steel, nitinol, titanium or alloys thereof. 5.The endoscopic snare net of claim 1, wherein the metal is of a steel. 6.The endoscopic snare net of claim 1, wherein the tube has a collardisposed within the lumen and the collar is fixed to the wall of thetube in a position at a distance from an end of the tube.
 7. Theendoscopic snare net of claim 6, further comprising a tether, whereinthe tether is coupled to the collar at a first end of the tether and tothe net at a second end of the tether, opposite of the first end.
 8. Theendoscopic snare net of claim 1, wherein the tube has a collar disposedwithin the lumen and the collar is free floating within the tube anddisposed around a control wire coupled to the loop.
 9. The endoscopicsnare net of claim 8, further comprising a tether, wherein the tether iscoupled to the collar at a first end of the tether and to the net at asecond end of the tether, opposite of the first end.
 10. The endoscopicsnare net of claim 9, wherein a length of the tether is selected suchthat the tether engages the net withdrawing the net into the tube, whenproximal end of the shaped loop enters the tube during retraction of theshaped loop and net.
 11. The endoscopic snare net of claim 10, whereinthe one or more corners are crimped and provide one or more resilientbends in addition to any bends that bias the loop open.
 12. Theendoscopic snare net of claim 11, wherein the one or more corners securethe net on the loop during closing, and the net is secured to the distalend of the loop only by a single point of attachment at the distal endof the loop.
 13. The endoscopic snare net of claim 1, wherein the one ormore corners comprises at least a first corner on a first side of theproximal end of the loop and a second corner on a second side of theproximal end of the loop, opposite of the first side such that adistinct pocket is formed within the net as the proximal end of the loopand the net are pulled into the tube, as the loop closes.
 14. Theendoscopic snare net of claim 1, wherein the one or more corners areopen such that the loop does not extend over any other portion of theloop.
 15. The endoscopic snare net of claim 14, wherein each of the oneor more corners comprises a first bend in a first bend angulardirection, a second bend in a second bend angular direction, opposite ofthe first bend angular direction, and a third bend in a third bendangular direction opposite of the second bend angular direction,arranged such that each of the one or more corners extends outwardlyfrom an imaginary line extending from a central longitudinal axis of thetube, when the loop is extended from the tube.
 16. The endoscopic snarenet of claim 15, wherein the first bend angular direction is moreinwardly divergent than the angular direction of an adjacent portion ofthe loop closer to the proximal end of the loop, the second bend angulardirection is more outwardly divergent than the first bend angulardirection, and the third bend angular direction is more inwardlydivergent than the second bend angular direction, whereby an outwardlyextending corner is formed at a outward vertex where the loop extendingalong the second bend angular direction diverges toward the third bendangular direction and an inwardly extending bend is formed at an inwardvertex where the loop extending from the first bend angular directiondiverges toward the second bend angular direction.
 17. The endoscopicsnare net of claim 16, wherein the one or more corners form at least onezig-zag in a portion of the loop.
 18. The endoscopic snare net of claim8, further comprising a loop anchor coupling the loop to the controlwire, wherein the collar is sized with an inner collar diameter that isgreater than an outer wire diameter of the control wire, and the loopanchor has a loop anchor outer diameter greater than the inner collardiameter of the collar, such that the collar cannot slide past the loopanchor outer diameter.
 19. An endoscopic snare net comprising: a loophaving a distal end of the loop and a proximal end of the loop; a net; atube having a lumen configured and arranged to accept the introductionof the loop and snare net through the lumen of the tube, wherein thelumen is defined by a wall of the tube, and the net is engaged on theshaped loop such that the engaged loop is woven through holes in the netsuch that the net is retained on the loop, the net being secured at thedistal end of the loop and, the distal end of the loop being shaped toexpand as the distal end of the loop exits the lumen first, and theproximal end of the loop having bends such that the loop continues toextend outwardly as the proximal end of the loop is extended beyond thelumen; a loop anchor; a free-floating collar, wherein the collar isdisposed within the tube and around a control wire, the collar beingsized with an inner collar diameter that is greater than an outer wirediameter of the control wire, and the loop anchor couples the controlwire to the loop, and the loop anchor has a loop anchor outer diametergreater than the inner collar diameter of the collar, such that thecollar cannot slide past the loop anchor; and a tether is coupled to thecollar at a first end of the tether and to the net at a second end ofthe tether, opposite of the first end such that the tether is not fixedto the control wire and is not fixed to the tube, and the tether tethersthe net to the free-floating collar.
 20. A method of using theendoscopic snare net of claim 1, comprising: extending the net and theloop from the lumen such that the loop opens; positioning the net andloop endoscopically to retrieve an object; withdrawing the net and loopat least partially back into the lumen, causing the loop to at leastpartially close and creating a pocket in the net, one or more of thecorners engaging a portion of the net near the proximal end of the loop,such that the portion of the net is pulled into the lumen by the one ormore corners, when the loop is withdrawn into the lumen.